Re: Bumping block size to 16K on FreeBSD...

Sean, can we get a copy of your test set?  And any scripts that you have
for running the tests?


On Thu, 28 Aug 2003, Tom Lane wrote:

> Sean Chittenden <sean@chittenden.org> writes:
> > Early performance tests on my laptop suggest it's about 8% faster for
> > writing when both the FS and PostgreSQL use 16K blocks.
>
> BTW, I don't really believe that one set of tests, conducted on one
> single machine, are anywhere near enough justification for changing this
> value.  Especially not if it's a laptop rather than a typical server
> configuration.  You've got considerably less I/O bandwidth in proportion
> to CPU horsepower than a server.  Why is that an issue?  Well, a larger
> block size will substantially increase our WAL overhead (because we tend
> to dump whole blocks into WAL at the slightest provocation) and on
> slower machines the CRC64 calculations involved in WAL entries are a
> significant cost.  On a machine with less CPU and more disk horsepower
> than you tested, the tradeoffs could be a lot different.
>
>             regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
>                http://archives.postgresql.org
>